<template>
  <el-container class="home-container">
    <!-- 头部区域 -->
    <el-header>
      <div>
        <img src="../assets/logo.png" alt="">
        <span>电商管理后台系统</span>
      </div>
      <el-button @click="exit" type="info">退出</el-button>
    </el-header>
    <!-- 内容区 -->
    <el-container>
      <!-- 左侧导航菜单 -->
      <el-aside :width="setWidth">
        <!-- 菜单折叠按钮 -->
        <div class="toggle-button" @click="toggleCollapse">|||</div>
        <!-- 侧边栏菜单区域 -->
        <el-menu background-color="#333744" text-color="#fff" active-text-color="#409EFF" unique-opened :collapse="isCollapse" :collapse-transition="false" router :default-active="activePath">
          <!-- 一级菜单 -->
          <el-submenu :index="item.id + ''" v-for="item in menuList" :key="item.id">
            <!-- 一级菜单的模板区域 -->
            <template slot="title">
              <!-- 图标 -->
              <i :class="iconsObj[item.id]"></i>
              <!-- 文本 -->
              <span>{{item.authName}}</span>
            </template>
            <!-- 二级菜单 -->
            <el-menu-item :index="'/' + subItem.path" v-for="subItem in item.children" :key="subItem.id" @click="saveNavState('/' + subItem.path)">
              <!-- 二级菜单模版区域 -->
              <template slot="title">
                <!-- 图标 -->
                <i class="el-icon-menu"></i>
                <!-- 文本 -->
                <span>{{subItem.authName}}</span>
              </template>
           </el-menu-item>
         </el-submenu>
        </el-menu>
      </el-aside>
      <!-- 右侧内容区域 -->
      <el-main>
        <!-- 路由占位符 -->
        <router-view></router-view>
      </el-main>
    </el-container>
  </el-container>
</template>
<script>
export default {
  computed: {
    setWidth () {
      if (this.isCollapse) {
        return '64px'
      } else {
        return '200px'
      }
    }
  },
  data () {
    return {
      // 存储列表数据
      menuList: [],
      // 添加字体图标 -- 暂时的解决方案
      iconsObj: {
        125: 'iconfont icon-user',
        103: 'iconfont icon-tijikongjian',
        101: 'iconfont icon-shangpin',
        102: 'iconfont icon-danju',
        145: 'iconfont icon-baobiao'
      },
      // 是否只展开一个
      isCollapse: false,
      // 链接激活状态
      activePath: ''
    }
  },
  created () {
    // 组件创建完成发起请求，获取菜单列表
    this.getMenuList()
    // 刷新页面，保持二级标题是选中状态
    this.activePath = window.sessionStorage.getItem('activePath')
  },
  methods: {
    exit () {
      // 清空本地存储的数据
      window.sessionStorage.clear()
      // 重定向到登录页面
      this.$router.push('/login')
    },
    // 获取所有菜单
    async getMenuList () {
      const { data: res } = await this.$http.get('menus')
      if (res.meta.status !== 200) return this.$message.error(res.meta.msg)
      this.menuList = res.data
    },
    // 展开或者折叠菜单栏
    toggleCollapse () {
      this.isCollapse = !this.isCollapse
    },
    // 保存激活链接状态
    saveNavState (activePath) {
      window.sessionStorage.setItem('activePath', activePath)
      this.activePath = activePath
    }
  }
}
</script>
<style lang="less" scoped>
.home-container {
  height: 100%;
}
.el-header {
  background-color: #373d41;
  display: flex;
  justify-content: space-between;
  padding-left: 0;
  align-items: center;
  color: #fff;
  font-size: 20px;
  > div {
    display: flex;
    align-items: center;
    span {
      margin-left: 15px;
    }
  }
}

.el-aside {
  background-color: #333744;
  // 解决一、二级标题右侧展开对不齐
  .el-menu {
    border-right: none;
  }
}

.el-main {
  background-color: #eaedf1;
}

// 字体图标和标题之间添加间距
.iconfont {
  margin-right: 10px;
}

// 折叠菜单按钮
.toggle-button {
  background-color: #4a5064;
  font-size: 10px;
  line-height: 24px;
  color: #fff;
  text-align: center;
  letter-spacing: 0.2em;
  cursor: pointer;
}
</style>
